Adjuvant Chemotherapy More Effective in Reducing Distant Pancreatic Cancer Metastasis
Adjuvant chemotherapy reduces distant recurrences of pancreatic ductal adenocarcinoma, according to a new study. Adding radiotherapy to chemotherapy and surgery reduced the number of local disease recurrences but did not affect distant recurrences or survival.1
This is the first multicenter clinical trial to relate disease recurrence patterns to the type of adjuvant therapy. It indicates that patients should receive a full course of chemotherapy rather than chemoradiotherapy following surgical treatment for pancreatic cancer.
Survival and disease recurrence were evaluated in 1130 patients who underwent successful surgical resection for pancreatic cancer between January 2000 and December 2010. Most patients had grade 2, Stage II disease (grade 4, Stage IV is the most advanced), and they received no treatment for cancer prior to surgery.
An estimated 48 960 cases of pancreatic cancer are diagnosed in the United States each year, and it is the 4th most common cause of cancer death. Most patients present with locally advanced or metastatic disease at diagnosis, therefore only 10% to 15% of patients are candidates for a potentially curative operation. Even when surgical resection is successful, recurrence is common. Recurrences occur in 50% to 90% of patients, and most of these patients die of the disease.
The high incidence of recurrence has led to routine adjuvant therapy after surgery for pancreatic cancer. The adjuvant therapy is typically systemic chemotherapy with or without chemoradiotherapy.
This study is the first to examine the relationship between adjuvant chemotherapy and chemotherapy plus radiation on the patterns of disease recurrence and overall survival after primary surgical resection of pancreatic cancer, explained Alexander A. Parikh, MD, MPH, FACS, associate professor of Surgery at Vanderbilt University, Nashville, Tennessee, and first author on the study. The study was conducted by the Central Pancreatic Consortium (CPC), which includes nine academic medical centers that treat high volumes of patients with pancreatic cancer.
"Individual institutions may differ slightly in the way they treat pancreatic cancer patients. When we do a collective, multicenter study, we decrease those differences and can provide insights that reflect the majority of what good pancreatic cancer care in America is," Parikh said.
The researchers assessed the patterns of disease recurrence in 3 groups of patients: those who underwent a surgical procedure alone, those who received adjuvant chemotherapy, and those who underwent radiotherapy in addition to chemotherapy. Patients were followed for a median period of 18 months.
Overall survival was improved by 29% with adjuvant chemotherapy compared with surgery alone, but chemoradiation did not significantly improve survival. Although the incidence of local recurrence was significantly decreased by both chemotherapy (41%) and chemoradiation (49%), the incidence of distant recurrence was significantly lower only after chemotherapy (26%) and was not affected by chemoradiation.
"Unless we get better evidence to show that radiation helps in resected pancreatic cancer, we believe adjuvant therapy should be confined to chemotherapy after surgery," Parikh said.
Parikh pointed out that while delivering adjuvant chemoradiotherapy, physicians significantly reduce the amount of chemotherapy that is administered.
"All patients should get at least 6 months of chemotherapy. If there is a role for chemoradiotherapy, it should not be given at the expense of giving less chemotherapy," he concluded.
1. Parikh AA, Maiga A, Bentrem D, et al. Adjuvant therapy in pancreas cancer: does it influence patterns of recurrence? [published online ahead of print February 13, 2016]. J Am Coll Surg. doi:10.1016/j.jamcollsurg.2015.12.031.